Banca de DEFESA: Águeda Lourenço Vieira da Silva

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Águeda Lourenço Vieira da Silva
DATE: 10/10/2023
TIME: 14:00
LOCAL: Remota (virtual)
TITLE:

"Ecology of interactions between plants and small mammals in the Cerrado: assessment of sampling design, effects of fire severity, and resource availability".

KEY WORDS:

diversity estimates, wildfire, plant-animal interaction networks, seed dispersal, rodents, marsupials, neotropical savanna.

PAGES: 144
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

The distribution of species and their ecological interactions varies spatially and temporally. Biological communities and consequently their interactions can be affected by disturbances such as fires, which are capable of altering the structure of habitats and the availability of resources. To understand species distribution patterns, as well as detect changes following disturbances, it is necessary to adequately measure the diversity of the groups studied. This is a challenge, especially for highly diverse groups, such as neotropical non-volant small mammals, and in environments composed of distinct plant physiognomies, such as the Cerrado (neotropical savanna). In this study, we evaluated: 1) how the sampling design affects estimates of small mammal diversity in the Cerrado; 2) the effects of fire severity, resource availability, and habitat structure on plant-animal interaction networks in which small mammals participate in the Cerrado; and 3) the effects of fire severity on the potential for seed dispersal by small mammals in the Cerrado. The kind of trapping protocol used to sample small mammal communities in the Cerrado affected the abundance and richness estimates of this group. Sampling designs using both cage traps and pitfalls and considering both climatic seasons (i.e., dry and rainy) were more efficient, especially in open formations. DNA metabarcoding analysis allowed us to detect a high number of plants consumed by rodents and marsupials far above what is possible using traditional methods. In total, we identified 211 species of plants in the fecal samples, contrasting with the 28 species of seeds detected by stereoscopic visual analysis. Plant-animal interactions between small mammals and Cerrado flora were affected by fire. The severity of fire made the interaction networks more nested, and with a lower degree of modularity and specialization in gallery forests more severely affected by fire. In these areas, the diversity of interactions was higher, possibly because of the invasion of species typical of open habitats, favored by changes in the habitat structure caused by fire. The availability of resources (i.e. fruits) also affected the structure of plant-animal networks, although this availability was not directly related to the fire severity. Habitat structure did not directly affect the structure of plantanimal networks, but this factor was largely explained by fire severity. Therefore, it is possible that its effects on the structure of interactions were indirect. Fire also affected the role of small mammals as potential seed dispersers. There was a reduction in the number of potential dispersers and in the diversity of plants dispersed by the group in the gallery forests most severely affected by fire. These effects were species-specific, varying along the fire severity gradient. The results presented in the present study indicate that severe fires modify the communities of small mammals that inhabit gallery forests even three years after the fire occurrence. These modifications have effects on plant-animal interactions as well as on the ecosystem roles that rodents and marsupials play as seed dispersers, potentially impacting plant recruitment in fire-sensitive areas. Considering this, we recommend that integrated fire management plans consider the protection of the most sensitive environments, as the negative effects of severe fires in these areas can be perceived on a long-term basis.

COMMITTEE MEMBERS:
Externa à Instituição - ELIANA CAZETTA - UESC
Presidente - 1653455 - EMERSON MONTEIRO VIEIRA
Interna - 404908 - HELOISA SINATORA MIRANDA
Externo à Instituição - MARIO ALMEIDA NETO
Interno - 1147029 - PEDRO HENRIQUE BRUM TOGNI